It's actually the primer compound that is corrosive, not the powder. Corrosive primers contain potassium perchlorate, which decomposes when ignited into potassium chloride, an alkali metal salt, similar to table salt (sodium chloride) that will attract moisture from the air and accelerate rusting. Modern primers contain lead styphnate as their oxidizer, which is non-corrosive.

The problem with firing those in a gas operated semi-auto is that, if they are corrosive primers, you'll have to take the whole gas system apart to clean out every part that the gas came in contact with or it will rust very fast. If you were shooting a bolt action rifle, I'd say go ahead and shoot them and then rinse the bore out with water, which will dissolve the KCl and flush it away. In a semi-auto, flushing the gas system with water isn't the greatest idea because getting everything dry and protected might be hard. I'd say don't shoot them in your 7400. Not worth the trouble.

Mike